Parents of Apopka High School students received an unnerving phone call Friday.

Principal Matthew Arnold’s voice played on a recording sent out to parents and guardians, informing them that administrators heard that rumors were circulating about “a possible threat” made against the high school that has more than 3,000 students.

“We take these matters very seriously, and will continue to work with law enforcement to provide a safe learning environment for our students,” Arnold said in the call.

Arnold said teachers and administrators are being “extra vigilant” on campus Friday. He said the Apopka Police Department is providing extra resources to the school, as well.

Arnold did not elaborate on the nature of the possible threat, or when it may have been made.

The Apopka Police Department did not immediately respond to a request for comment.